Synthesis of M600-Functionalized ZIF-67 and Application in Mixed Matrix Membrane for CO2 Separation

The development of high-performance mixed-matrix membranes (MMMs) for CO 2 separation requires fillers that simultaneously offer molecular-sieving pathways and favorable interfacial compatibility. Here, ZIF-67 was grafted with a long-chain polyetheramine (M600) to yield ZIF-67-M600, which was then incorporated into a Pebax matrix to fabricate novel MMMs. Comprehensive characterization including FT-IR, XRD, SEM, DSC and TGA confirmed the successful grafting of M600 and the homogeneous dispersion of the filler within the polymer. The microporous framework of ZIF-67 provides size-selective transport channels, while the abundant ether groups in M600 enhance CO 2 affinity and facilitate its preferential diffusion. Gas permeation tests demonstrate that the 4 wt% ZIF-67-M600/Pebax membrane achieves a CO 2 permeability of 110.12 Barrer and a CO 2 /N 2 selectivity of 85.96°C at 30°C and 0.2 MPa, corresponding to increases of 65% and 61%, respectively, compared to the pristine Pebax membrane. This performance surpasses the 2008 Robeson upper bound, highlighting that surface grafting of MOFs with CO 2 -philic polymers is an effective strategy to concurrently boost permeability, selectivity, and interfacial adhesion in MMMs for advanced gas separation.